Struct Iters 

pub struct Iters { /* private fields */ }

The number of iterations for PBKDF.

The general rule is bigger is better (in terms of security), however, bigger is also more computationally expensive.

OWASP recommends using at least 600,000 iterations with SHA256 for passwords, a FIPS requirement. NIST SP 800-132, Section 5.2, back in 2010, recommends anywhere from 1,000 to 10,000,000 iterations (10,000,000 for critical secrets). However SP 800-132 is under active revision, and the lower bound of 1,000 iterations is now considered inadequate for modern security needs.

Implementations

impl Iters

pub const fn new(iters: u32) -> Option<Self>

Create a new Iters instance.

Note

Please see the Iters type documentation for more information and sources to assist in picking the correct value. The value is context dependent, are you hashing a password? You’ll need a very large value, minimum 600,000. For key derivation, again it is context dependent, how critical is this key? How powerful is the host machine? The general rule is the bigger the value, the better in terms of security.

Arguments

• iters - The desired number of iterations (must be non-zero).

Returns

• Some(Iters): The new Iters instance.
• None: The provided iters argument was zero.

pub const unsafe fn new_unchecked(iters: u32) -> Self

Create a new Iters instance without any safety checks.

Safety

This will cause undefined behavior if the provided iters argument is 0. Iters may only be constructed with non-zero values (as the underlying type is NonZeroU32).

pub const fn is_valid_size(&self) -> bool

Returns true if the iteration count can safely be cast to an i32.

Certain KDFs (such as the PBKDF family) take the iteration count as an i32, and check at runtime if the iteration count is greater than 0. This most likely is an older design choice which they must keep for stability reasons.

For ergonomic reasons, we will represent the iteration count as an unsigned int.

pub const fn get(&self) -> u32

Returns the contained iteration count as a u32.

Trait Implementations

impl Clone for Iters

fn clone(&self) -> Iters

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Iters

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Iters

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<NonZero<u32>> for Iters

fn from(value: NonZeroU32) -> Self

Converts to this type from the input type.

impl Ord for Iters

fn cmp(&self, other: &Iters) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Iters

fn eq(&self, other: &Iters) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Iters

fn partial_cmp(&self, other: &Iters) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl TryFrom<u32> for Iters

fn try_from(value: u32) -> Result<Self, Self::Error>

Create a new Iters instance from a u32.

Errors

If the number of iterations was zero.

type Error = InvalidIters

The type returned in the event of a conversion error.

impl TryFrom<usize> for Iters

fn try_from(value: usize) -> Result<Self, Self::Error>

Create a new Iters instance from a usize.

Errors

• If the number of iterations was zero.
• If the number of iterations was greater than u32::MAX.

type Error = InvalidIters

The type returned in the event of a conversion error.

impl Copy for Iters

impl Eq for Iters

impl StructuralPartialEq for Iters